<div id="app"></div>

<script type="module">
  import { createApp, ref,watchEffect } from './vue.esm-browser.js'

  createApp({
    template:`{{message}}
        <h1>{{count}}</h1>
        <button @click="count++">change</button>
    `,
    setup() {
      const message = ref('Hello Vue!')
      const count=ref(0)
      watchEffect(() => {
          console.warn(message.value,count.value);
          count.value++;
      });      
      return {
        message,
        count
      }
    }
  }).mount('#app')
</script>